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Have scientists found the elixir of youth?

MARK COLVIN: Scientists may be a step closer to the secrets of a longer life.

Three studies in the US have found that a drug called rapamycin is capable of extending the life expectancy of mice.

Now, researchers are looking into what these findings could mean for humans.

Kathryn Stolarchuk has this report.

KATHRYN STOLARCHUK: The drug rapamycin was discovered in a soil sample taken from Easter Island in the 1970s and has since been beneficial in treating a variety of medical conditions.

Now it could be used to one day boost human life expectancy.

In tests on middle-aged mice, which are mice that are about 20 months old, the drug increased life expectancy by up to more than a third.

Arlan Richardson is the director of the Barshop Institute, which is one of the centres that carried out the experiments.

ARLAN RICHARDSON: What they've shown here is that for the first time it's possible to use a drug or a single compound and feed it to a mammal, a mouse, which is fairly similar to human beings and these mice will live longer. This is the first demonstration that there might be an anti-ageing pill available in the future

KATHRYN STOLARCHUK: He says the discovery will have major repercussions for society.

ARLAN RICHARDSON: So theoretically this could be used to treat age-related diseases such as cancer, heart disease, maybe even neurodegenerative diseases like Alzheimer's and Parkinson's. And so my guess would be is that in the near future there would be clinical studies that would be looking into the feasibility of using this in treatment. I know that there are studies ongoing now in using rapamycin in cancer treatments and therapies.

KATHRYN STOLARCHUK: Brian Kennedy is a biochemist at the University of Washington.

He says that if the claims are true then it would be a big step in medical research.

BRIAN KENNEDY: If there's a drug that can slow the rate of ageing it will provide a protective mechanism against a whole range of these different diseases and that remains to be shown but we're getting to the point in ageing research where we can directly test this idea

KATHRYN STOLARCHUK: But he says it's unclear if the drug would have similar effects in humans.

BRIAN KENNEDY: Rapamycin has potential negative side effects that may preclude its use in humans. What we don't know is whether long-term chronic exposure at low doses, which is what the mice were given, will give rise to these negative effects as well and so it's not time for people to go out and try to get this drug to slow their rate of ageing.

But I think it is exciting because it's the first drug that offers that potential down the road and I think there'll be more drugs coming along that have similar affects and the key will be finding the right ones that give you the benefits and don't have the negative consequences

KATHRYN STOLARCHUK: Dr Richardson says he can understand why people are sceptical.

ARLAN RICHARDSON: I would have been one of those sceptics about a year ago, or even six months ago. I've been involved in ageing research for about 30 years, 35 years, and about every couple of years there's something that's touted will slowdown ageing and I had assumed that we would not find a drug or a compound that would do it in my lifespan and so what I would say to the sceptics is this is probably the best controlled study; it was done at three sites and they replicated it at all three sites.

KATHRYN STOLARCHUK: So although the concept of an anti-ageing pill sounds good in theory, there are no guarantees and we all might age a little more before the research is completed.